Engineers level

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Doug,

That is a very interesting difference, and may help explain why some find 'levelling' easier than others!

My guess is that 0.02mm per m is too sensitive for practical use.

MichaelG.

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P.S ... The build quality of that 0.02 level is what really worries me ... [See Nealeb's description, posted earlier today]

It's very easy to make a ridiculously senitive vial [in extremis; a straight tube]; but that doen't guarantee a useful instrument.

Edited By Michael Gilligan on 01/01/2015 20:22:17

Edited By Michael Gilligan on 01/01/2015 20:24:37

Hi there, all,

Some time ago I bought a level (clinometer ?) like the one Clive shows in his post. Unfortunately, the bubble is longer than the scaled part of the tube - I suspect it has invited a few relatives in for Christmas!

I'd replace the tube if I could obtain a suitable one - what is members' experience regarding availability of spare tubes? I dimly remember a link to Cromwell's web-site but can't retrieve it now.

Best regards,

Swarf, Mostly!

It's not exactly the best-made tool in my garage! But the bottom is flat, the graduations are about right, and the adjusting screw is fine enough to be able to zero it with an end-for-end check. The great thing about a level is that it is self-checking. I'm happy that I have my money's worth, given the price of even second-hand levels from a recognised manufacturer. I would agree that 0.02mm/m is very sensitive. I'm using it with feelers to measure differences in level and I am regularly needing the 0.05mm feeler to bring the bubble on-scale.

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Thanks for the update, Nealeb

I'm glad to know you're happy with it.

MichaelG.

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I haven't yet had need to use them, but Level Developments would be a good place to start.

MichaelG.

Now there's a thought. after looking at the link above I have a bench drill in my shed not the best thing for accurate drilling as the thing has so many movements drilling anything thicker than 1mm and it's pain to get drill set up to run without being at an angle (its got them pointless stick on bits of tape with 1mm +/- divisions). So if I get some of these vials I can fix them around drill so I can see every thing is ok.

Hi Michael, I tend to agree, the one I have is not much use for general work, the slightest movement of the floor that you stand on moves the bubble significantly, even leaning more on one foot more than the other and even placing your hand on anything that potenionaly deflects will move the bubble.

Below is a photo of each end of the bubble mounting and to my mind the adjusting thread is a little too course to truely set it dead centre when level. It's a long and painstaking job to get it even close, one day I may attempt to replace the adjusting screw and nuts wirth finer ones.

Regards Nick.

> anyone care to explain if the levels should be observed locally or from a remote?

It doesn't matter, the act of measuring will impact on the system, however you do it. Even placing a level on the lathe bed will deflect it...

Neil

*This is why the Lunar Society met at full moon, at least they could be sure the tidal forces on their experiments were constant.

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As my old pal Alec used to say: "B***S*** baffles brains"

MichaelG.

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John,

Although are no 'list' prices shown for the ground-tube precision vials; the general purpose ones are priced on the website ... [example] ... and they seem keen to accept enquiries about the others.

MichaelG.

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That's why I posted my comment.

> And I always thought it was to have light to get home by.

A vicious rumour spread by their London-based rivals.

Neil

Careful Neil. We're getting into the realms of quantum physics and heisenberg's Uncertainty Principle!

Russell.

I got a lift to the pub today, again. Talking to a mate who was telling the story about when he was a fully trained machine man. Spent about 2 weeks scraping and leveling a big lathe, put slings on to turn it round and do more work. Set down ready for work and of course it was all out again PS this was true even if no one was looking at it.

Ah but how do you know?

Russell.

Because he told me so, he is and was stone deaf , would the speed of sound change?

It seems to me that, in an amateurs workshop, the only important thing is to make sure the bed isn't twisted when bolted down; the quickest way to detect this is with an accurate spirit level across the bed at each end. However this spirit level is used as a comparator so actual calibration is not important. Many lathes, including mine, have never been checked in this way and still turn accurately. It will come as a surprise to many amateurs that a steel bar 1"x2" and 18" long will measurably sag under its own weight so a bar in the lathe can do the same which would indicate that there is no point in being too concerned with extreme levelling precision. Colin

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Colin,

A the risk of starting another civil war, by the mere mention of his name:

It is worth noting that Dr. Georg Schlesinger specifies a Test Mandrel which is hollowed-out, to avoid sag [and was using such mandrels in 1902].

MichaelG.

I intend to use a 2" alloy tube, 6mm wall thickness so sag should be less of a problem, but all in all it will depend on how accurate you can measure, me down to probably less than 0.005mm and if you are using a micrometer depends on how good you are getting repeatability.

Bob